Equilibrium point of an array is a point when the left sum is equal to the right sum .
Input : -1 , 8 , 4 , 9 , -2
Output : 4
Because the left sum of 4 is (-1+8) which is 7 and the right sum is (9-2) which is again 7 . Both the sides are perfectly balanced hence it is an equilibrium point .
Input : 3 , 4 , 8 , -9 , 20 , 6
Output : 20 (Here 3+4+8-9 is equal to 6 , hence 20 is the equilibrium point ).
Here we have 2 codes . One is in Java and the second one is in C++ .
Java Code :
public class ArrayE
{
public static int equilibrium(int[] arr)
{
int sum=0;
int check_sum=0;
int left_sum=arr[0];
for(int i=0;i<arr.length;i++)
{
sum+=arr[i];
}
for(int i=1;i<arr.length;i++)
{
if(sum-left_sum==check_sum)
return arr[i-1];
else{
check_sum+=arr[i-1];
left_sum+=arr[i];
}
}
return -1;
}
public static void main(String [] args)
{
int [] arr ={-1,8,4,9,-2};
System.out.print(equilibrium(arr));
}
}
C++ Code :
public class ArrayE
{
public static int equilibrium(int[] arr)
{
int length = sizeof(arr)/sizeof(arr[0]);
int sum=0;
int check_sum=0;
int left_sum=arr[0];
for(int i=0;i<length;i++)
{
sum+=arr[i];
}
for(int i=1;i<length;i++)
{
if(sum-left_sum==check_sum)
return arr[i-1];
else{
check_sum+=arr[i-1];
left_sum+=arr[i];
}
}
return -1;
}
int main()
{
int [] arr ={-1,8,4,9,-2};
cout<<equilibrium(arr);
}
}
